The beneficial effects of adding fluoride to drinking water are well known. Fluoride at a concentration of about one part per million (ppm) is known to greatly reduce tooth decay, contribute to good bone health, and may also substantially reduce osteoporosis in post-menopausal women. It is also known, however, that high levels of fluorine can be toxic and a strong irritant to human tissue. Nevertheless, it is established that concentrations of fluoride at about 1 ppm, levels known to provide the health benefits, are well below the amounts resulting in adverse health effects. Consequently, it is important if fluoride is added to drinking water that the concentration be maintained and controlled near such levels.
Because of the beneficial health benefits of low levels of fluoride, many cities and municipalities have undertaken a fluoridation program adding a fluoride salt to public drinking water to achieve the about 1 ppm concentration of the fluoride. For instance, it is common for larger cities or municipalities to add a fluosilicic acid, sodium silicofluoride, or sodium fluoride to the city water supply as a part of the fluoridation program. In a large water system, such as a water processing facility that typically processes greater than about 30,000,000 gallons of water daily, it is feasible to achieve consistent, low-levels of fluoride in the drinking water using a variety of common chemical feed pumps, such as peristaltic or pulse-feed pumps at the water processing facility. Because the large water facility processes considerable volumes of water, such pumps are effective at providing, maintaining, and controlling the fluoride at the about 1 ppm concentration.
In smaller water systems, it is often not feasible to duplicate the fluoridation programs of the larger systems due to the difficulty of providing a consistent and low concentration of the fluoride in a smaller volume of water. Current peristaltic and pulse-feed pumps are not only expensive, but often are unable to provide the fluoride in small enough levels to consistently maintain about 1 ppm concentration in a low volume of water. Even utilizing very high-cost precision pumps, the metering of fluoride in low volumes of water at levels of 1 ppm consistently is often difficult to achieve and maintain. As a result, many small municipalities, such as cities that operate a water processing facility that typically processes less than about 60,000 gallons of water daily, usually do not undertake a fluoridation program because of the expense and difficulty in achieving and controlling the required low levels of fluoride in the water streams.
Likewise, individual homes in rural areas often do not fluoridate their water because such homes usually obtain water from individual wells, shared wells, or spring boxes. Efficiently fluoridating these individual water supplies is also very difficult for similar reasons. Moreover, in an individual home water system, such as the well, the volumes of water are substantially lower than the amounts processed by the small water processing facility; as such, even greater difficulties are encountered in supplying and maintaining a fluoride concentration of about 1 ppm in such home water systems.
In addition, other chemicals are often added to a variety of fluids in low levels for numerous reasons, such as disinfecting, maintaining proper pH, maintaining proper alkalinity levels, and the like. Often it is desired to achieve such characteristics in a continuous, low volume process. In such a process, similar difficulties arise when attempting to achieve consistent and low concentrations of chemicals in the fluid.
As a result, it is desired to obtain a system and method of supplying a consistent, low concentration of a chemical to a fluid that is cost effective and easy to maintain and control such low concentrations.